The present invention relates to the field of fluid compositions for application to the body, and more particularly to spray compositions which have a reduced tendency to run or drip.
Nasal sprays have been used for many years by persons suffering from nasal disorders, such as infections or allergic manifestations. Among the pharmaceutical agents commonly delivered intranasally are antihistamines, antiinflammatory drugs, decongestants, antimuscarinics, antibiotics, anesthetics and moisturizers. In addition, it is possible to deliver agents intranasally to achieve systemic effects through absorption across the well-vascularized mucosal membranes; certain vaccines, analgesics and other prophylactic or therapeutic substances can be efficiently administered in this manner.
Various spray compositions are also known for application other than intranasally, such as breath freshener and analgesic sprays for the mouth and pharynx and antiseptic sprays for skin application of medicinal or cosmetic compositions.
A common problem with spray administration is a low efficiency of the active agent, since the structure of body cavities and parts does not typically facilitate retention of the applied formulation. This is particularly the case for aqueous-base nasal spray formulations, which must have sufficient fluidity to be dispensed by a pump device or a squeeze-type spray bottle, but which can simply drain from the nose or pass through the nose and into the pharynx while, or immediately after, being sprayed. Moreover, due to ciliation of the nasal passages and movement of air through the nose, even materials applied in particulate form, such as by a pressurized metered dose inhaler or a powdered drug inhaler, are rapidly cleared from the nose. Several of the possible active agents or other formulation components have a quite unpleasant taste, so it is desirable to minimize the amount of the formulation which is not retained within the nose for at least the minimum time required to obtain the desired effect. Due to swallowing of much of the formulation which enters the oropharyngeal area, a large portion of the active agent introduced into the nose is generally rendered unavailable for its intended use.
Aqueous materials sprayed onto the oral, rectal or vaginal mucosa, or onto the skin, similarly have a tendency to run or drip, and therefore frequently are not retained in a desired location for sufficient time to accomplish the desired function, which may involve absorption of an active agent by the underlying tissues for a local or systemic effect.
International Patent Application WO 94/05330 describes a nasal spray product that forms a gel upon contact with mucous membranes, which product contains a crosslinked acrylic acid-based polymer. The product is alleged to exhibit a reduced tendency for xe2x80x9croll-back,xe2x80x9d where liquid exits the nose after spray application.
The product Nasacor(trademark) AQ nasal spray is an aqueous suspension of particles of the corticosteroid drug triamcinolone acetonide, and contains about 2 percent by weight of a mixture of microcrystalline cellulose and carboxymethylcellulose sodium, as a suspending agent. Such suspensions are described in U.S. Pat. No. 5,976,573.
The product Vancenase(trademark) AQ nasal spray is an aqueous suspension of the corticosteroid drug beclomethasone dipropionate monohydrate, containing about 1.5 percent by weight of a mixture of microcrystalline cellulose and carboxymethylcellulose sodium, as a suspending agent.
The product Nasonex(trademark) nasal spray is an aqueous suspension of the corticosteroid drug mometasone furoate monohydrate, containing about 2 percent by weight of a mixture of microcrystalline cellulose and carboxymethylcellulose sodium, as a suspending agent.
It would be desirable to provide an aqueous composition that can be made to have a viscosity sufficiently low to permit spraying with a standard pump mechanism or squeeze-type spray bottle, but which then rapidly exhibits a significant viscosity increase to retain the composition at the application site.
The present invention provides an aqueous-based sprayable composition containing a therapeutic or palliative agent, water and a mixture of microcrystalline cellulose and alkali metal carboxyalkylcellulose. The composition is a non-Newtonian, or thixotropic, fluid, exhibiting a reduced apparent viscosity while being subjected to shear forces, but a high apparent viscosity while at rest; this property permits application by spraying with readily available pump spray devices or squeeze-type spray bottles immediately following the application of a shearing force (such as those created by vigorously shaking the product container), but causes the sprayed material to remain at least temporarily relatively immobile on mucosal membranes or the skin. The preferred embodiments have a very rapid rate of viscosity recovery, following withdrawal of the shearing force.
The invention can be used to prepare many types of spray compositions, such as those for application to mucous membranes or the skin. In a particularly preferred form, the invention is an aqueous nasal spray containing a topically active decongestant.